This invention relates to an aquatic plant cutting apparatus capable of cutting efficiently, reliably and quickly those submersed plants and rooted plants with floating leaves or emersed plants which grow abnormally with eutrophication of rivers, lakes and ponds, and to an aquatic plant recovery boat equipped with such a cutting apparatus.
Generally, aquatic plants are classified into five groups, i.e. floating plants, rooted plants with floating leaves, submersed plants, emersed plants and wetland plants, in accordance with the forms of their growth. Several cutting apparatuses for the floating plants and the rooted plants with floating leaves have been proposed and have already been put into practical application.
On the other hand, the wetland plants have their roots fastened firmly into the soil; hence, they can be cut off by the same mowing method as with on-land weeds. Since the submersed plants float on the water surface and in water, however, they are driven out forward and cannot be cut off smoothly when a disc-like single edge cutter rotating at a high speed is brought close to them. As a result, the submersed plants having their roots in the river bed and growing in water must be removed by a herbicide or they are left as such in many cases. However, the use of the herbicide should be restricted because it greatly affects the environment. Accordingly, effective means for removing aquatic plants growing in reservoirs and raceways has been desired earnestly.
Among aquatic plant cutting apparatuses, a so-called "slide system" aquatic plant cutting apparatus wherein a cutter edge slides is known. The slide system aquatic plant cutting apparatus includes a two-edge system and a three-edge system. However, the two-edge system involves the problem that since the cutting edges themselves are small and since they move in a transverse direction with respect to an advancing direction of the aquatic plant cutting apparatus, the aquatic plants floating in water are pushed away in the advancing direction of the aquatic plant cutting apparatus and cannot be cut off smoothly.
On the other hand, one of the moving edges of the three-edge slide system has the function of restricting the aquatic plants and the other of the moving edges has the cutting function. Therefore, the three-edge system has higher aquatic plant cutting performance than the two-edge system but its operation speed is limited because the moving blades are of the slide type.